Field of the Invention
The present invention belongs to a process for the preparation of gelatine by enzymatic treatment of collagen.
Description of Related Art
Gelatin is a mixture of peptides and proteins obtained by solubilizing collagen. Collagen is predominantly extracted from various animal by-products such as bones and skin using an alkaline or acid pretreatment.
Traditionally gelatin may be extracted from collagen using hot water in a multi-stage extraction to solubilize collagen into gelatin. Typically, three temperature stages of hot water extraction can be used: (1) 50-55° C.; (2) 60-65° C.; and (3) 70-75° C. The higher the water temperature used in the extraction, the higher collagen solubilization is obtained, but lower gelatin strength. Collagen comprises three polypeptide strands, so-called alpha strands (alpha, alpha 1 and alpha 2) and during extraction these collagen peptides are solubilized. After solubilization further treatments may be applied to the gelatin (solubilized collagen), such as filtration, clarification, and drying.
Disadvantages of extracting gelatin using hot water is that large volumes of water are required and a long time is needed for the liming and extraction process.
As an alternative, enzymatic processes for extracting gelatin from collagen have been described. The enzymes are generally used to either improve or replace a pretreatment step in the gelatin process, such as liming, or to increase the yield gelatin during hot water extraction at a lower temperature.
CN102051130 compares the use of an acid protease, pepsin, and several neutral proteases for the extraction of gelatin from defatted demineralized bones. Disadvantages of the processes disclosed in CN102051130 are that a high amount of water was still needed in the gelatin extraction and that an extra heat step was applied to obtain a high yield of gelatin.
CN102329843 discloses the use of an acid protease from A. niger for the extraction of gelatin from bone collagen, wherein the enzymatic reaction needed to be carefully controlled to prevent overreaction of the enzyme.
A disadvantage of enzymatic methods for gelatin extraction known in the art is the non-specific proteolytic cleavage of collagen. The broad spectrum proteases used, generate, unless carefully controlled, small protein fragments and therefore lower the gelatin quality.
The aim of the present invention is an improved process for enzymatically extracting gelatin wherein a high quality of the gelatin is obtained at a high yield.